By mid-1991 Sino-American relations had reached their lowest point in almost 20 years. The roots of Sino-American rapprochement throughout the 1970s and 1980s lay in the so-called strategic triangle. The end of the Cold War in the late 1980s should have marked a significant shift in Sino-American ties. Many Americans had believed that Deng Xiaoping's China was changing in fundamental ways and that the new vision the Chinese were finding was based on Western values. Like the duality in American views of China, there is a duality in China's view of the United States. The Tiananmen massacre and subsequent nationwide political crackdown catapulted human rights into the forefront of issues affecting Sino-American relations. In spring 1990, the administration was out of touch with Congress's mood, which had not mellowed in the year after Tiananmen. Chinese government fears of cultural pollution in the wake of Tiananmen have also affected the exchanges.